Read excel and convert to Hashmap ConcurrentHashMap using Java

public static ConcurrentHashMap<String, ConcurrentHashMap<String, String>> dataMap = new ConcurrentHashMap<>();
	public static ConcurrentHashMap<String, String> cellValues = null;

	public static void main(String[] args) {
		getData();
		for (String key : dataMap.keySet()) {

			System.out.println(dataMap.get(key));
		}
	}

	private static Object getCellValue(Cell cell) {

		switch (cell.getCellType()) {
		case STRING:
			return cell.getStringCellValue();
		case NUMERIC:
			return cell.getNumericCellValue();

		case BOOLEAN:
			return cell.getBooleanCellValue();
		default:
			break;
		}

		return null;
	}

	public static void getData() {
		try {

			FileInputStream fis = new FileInputStream("Data/ServiceTesting.xlsx");
			XSSFWorkbook workbook = new XSSFWorkbook(fis);
			XSSFSheet sheet = workbook.getSheetAt(0);
			Iterator<Row> rowIterator = sheet.iterator();
			while (rowIterator.hasNext()) {
				Row row = rowIterator.next();
				Iterator<Cell> cellIterator = row.cellIterator();
				String key = row.getCell(0).toString();
				cellValues = new ConcurrentHashMap<>();
				while (cellIterator.hasNext()) {
					Cell cell = cellIterator.next();
					if (cell.getRowIndex() != 0) {

						String header = sheet.getRow(0).getCell(cell.getColumnIndex()).getStringCellValue();
						String clellValue = (String) getCellValue(cell);
						cellValues.put(header, clellValue);
					}

				}
				if (row.getRowNum() != 0) {
					dataMap.put(key, cellValues);
				}

			}
			workbook.close();
			fis.close();

		} catch (Exception e) {
			e.printStackTrace();
		}

	}